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Inhibitory effects of cinnamon, clove and celak extracts on growth of Aspergillus flavus and its aflatoxins after spraying on pistachio nuts before cold storage
Author(s) -
Khorasani Sepideh,
Azizi Mohammad Hossein,
Barzegar Mohsen,
HamidiEsfahani Zohreh,
KalbasiAshtari Ahmad
Publication year - 2017
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/jfs.12383
Subject(s) - aflatoxin , aspergillus flavus , food science , chemistry , food spoilage , eugenol , pistacia , aspergillus parasiticus , horticulture , biology , bacteria , genetics , organic chemistry
The essential oils of clove, cinnamon and celak extracted, diluted (at 3, 5, 7 and 9%), and UV‐sterilized. HPLC analysis showed that the clove, cinnamon and celak extracts had respectively eugenol (12.15 mg/g), cinamaldehyde (25.74 mg/g), and combination of thymol (14.49 mg/g) and carvacrol (1.17 mg/g). The Ohadi, Akbari, Ahmad‐Aghaei (AA) and Kalleh‐Ghouchi (CG) pistachio mixed with each dilution and extract (5% ratio) separately, sprayed with 1 ml of Aspergillus flavus ( Af ) spores (10 8 CFU/mL), and cold‐stored (1°C and 75% RH) 9 months. The aflatoxins of KG pistachio without herbal extract exceeded 1000 ppb after 3 months. However, the phenols of each extract with 9% concentration could inhibit 100% Af in each contaminated pistachio variety and destruct its aflatoxins efficiently even after 14 days of cold‐storage. The contaminated and extract‐sprayed Ohadi pistachio nuts had smallest size and weight among pistachios and its total aflatoxin < 35 ng/g (global standard) after 9 months of cold‐storage. Practical applications While pistachio with pleasant taste has a high international demand, it is a susceptible nut to Aspergillus flavus . This fungus contaminates high volume of even low moisture (∼5%) pistachio packages in less than 3 months during storage or transportation at high relative humidity. A. flavus produces different kinds of carcinogenic aflatoxins (as secondary metabolites) which threaten human health even at global and maximum acceptable level of 15 ng/g of pistachio. Since applying of the chemical disinfectants (even permissible ones) on pistachio kernels may leave residue with undesirable side‐effects on human health and natural environment, medicinal plants have been considered for their powerful antimicrobial activities. This study showed that separate spraying of three herbal plant extracts including cinnamon, clove and celak on pistachio kernels could inhibit entirely (100%) the growth of toxigenic fungi and destruct the produced aflatoxin when the nuts should be stored for more than 1 month.